Cannon-pinion



(No Model.)

J. B. JOBSON.

CANNON PINION. 190.1189933. Patented Nov. 99, 1892.

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UNITED STATES PATENT OFFICE.

JOHN B. JOBSON, OF MACON, GEORGIA.

CANNON-PINION.

SPECIFICATION forming part yof Letters Patent No. 486,933, dated November 29, 1892. l

Application led April l2, 1892. Serial No. 428,806. (No model.)

T0 all whom it may concern.-

Beit known that I, JOHN B. JOBSON, a citizen of the United States, residing at Macon, in the county of Bibb and State of Georgia, have invented certain new and useful Improvements in Oannon-Pinions; and I do declare the following to be a'full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to Inake and use the same.

The object of the present invention is to provide asimple and efficient means for firmly fastening the cannon-pinion of a watch or other timekeeper on its arbor.

With this end in view the invention consists in the combination, with an arbor, of a pinion having its axial opening made polygonal and provided with inclined side walls and a divided tempered friction-tube having at one end an undercut or flared protuberance which fits tightly in and bears against said inclined Walls of the polygonal axial opening in the pinion, whereby the divided end of the elastic friction-tube is expanded upon the pinion so as to securely hold the same in engagement With the friction-tube, and the lattel` is caused to tightly hug the arbor or engage the same with sufficient friction to prevent said tube and pinion from slipping on the arbor.

The invention further consists in the peculiar construction and arrangements of parts, as Willbehereinafterfullydescribedand claimed.

My improvements are fully illustrated in the accompanying drawings, forming a part of this specication, and in which- Figure l is a perspective view illustrating the arbor, the pinion, and the friction-tube connected together. Fig. 2 is a detail perspective view of the spring friction-tube detached from the arbor and pinion. Figs. 3 and 4 are views in elevation of the pinion, looking at the obversekand reverse sides thereof. Fig. 5 is a perspective view of part of the spring friction-tube, illustrating the undercut protuberance on the lower end of the friction-tube. Fig. 6 is a perspective view of the arbor and the parts associated and combined therewith for use. Fig. 7 is a longitudinal sectional View through the arbor, the pinion, and the friction-tube of my invention; and

Fig. 8 is a transverse sectional view on the line a: c of Fig. 7.

Like letters of reference denote corresponding parts in the several figures of the drawings, referring to Whiche- A designates the arbor,whicl1 is of the usual or any preferred form, and B is the pinion. This pinion is made or struck up of a single flat piece of metal, usuallyT of steel or any other preferred material, and on itsperiphery it is provided with the usual gearnteeth b. In the center of this pinion is provided an axial opening c, which is preferably polygonal in shape, as indicated in Figs. 3 and 4 of the drawings, although it may be made circular or of any preferred form. The walls of this axial opening are beveled or inclined, as at c', and the diameter of the axial opening on the reverse face or side of the pinion is thus made somewhat greater than the diameter of said opening on the obverse face or side of the opening, (see Figs. 3 and 4,) in which the reverse side of the pinion is shown in Fig. 4 and the obverse side of said pinion is shown in Fig. 3.

D is the split elastic friction-tube which hugs the arbor by tight frictional contact and engages with the pinion to hold the same rig'- idly in its proper position relatively to the arbor. This friction-tube is made of a single piece of steel of the requisite elasticity, and said tube is divided or split longitudinally nearly its entire length, as indicated in Figs. l, 2, 5, and 8. The ends of thefriction-tube are provided with the annular collars e e', which are somewhat larger in diameter than the intermediate or body portion ot' the tube, and the longitudinal slits or cutsf in the tube extend from the lower end of said tube, through the lower collar along the length of the tube, to or nearly to the collar on the upper end of said tube, all as shown in the drawings. The lower end of the friction-tube is provided Wi th a protuberance orhead G, which conforms in shape and size substantially to the axial opening c in the pinion, and this protuberance or head is undercut, as at g, to conform to the bevel or indentation of the Walls c in the axial opening c in the pinion, the head thus having the side faces or edges thereof inclined or beveled, as shown. To

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connect the parts together, the split end ot the friction-tube is compressed so as to force the tapered head together, and this head is then fitted in the axial opening in the pinion from the obverse side thereof, so that the beveled faces of the enlargement take or bear against the correspondingly-shaped Walls of the opening in the pinion, after which the divided or split part of the friction-tube is tempered to increase its elasticity, and which tends to somewhat reduce the diameter of said split part of the tube, and finally the tube is slipped or forced over the arbor, whereby the divided elastic part of the tube is expanded and is caused to tightly clasp itself upon the arbor and to firmly and immovably hold the pinion on the beveled head thereof. The friction-tube thus serves two important functions, that of holding the pinion in a rigid permanent position relative to the arbor and of firmly gripping the arbor so as to hold itself thereon solely by frietional contact. The lower divided end oi' the split tube lies flush with the reverse face of the pinion, and to the upper solid end of the friction-tube the minute-hand of the timekeeper is secured in any suitable manner.

It is essential to correct timekeeping of a watch that the cannon-pinion shall not be too loose on its arbor, as it would lose time, nor yet too tight on the arbor, and by my improvement I have overcome the serious objections that have heretofore existed in the ordinary methods of fastening the cannon-pin in place.

The improvement is very simple, inexpensive, and can be readily adapted by ordinary repairs, and at the same time it is very etticient and reliable.

Although I have shown and described the axial openingin the pinion and the protuberance or head on the split tube as being polygonal in form, yet I do not strictly confine myself to this particular shape, as it is evident that the form and proportions of parts and details of construction can be varied without departing from the spirit or sacrificing the advantages of my invention. Nor do I limit myself to the specific application or use of my invention in connection with time-keepers, but hold myself at liberty to use the means for fastening a gear pinion or wheel on a shaft in other machines or arts.

In stem-winding watches there is a tendencyforthe cannon-pinion to move upwardly while winding or setting the movements; but this objection is not present in the old-style or key-winding watches, for the reason that the operator in winding his watch with a key always exerts a downward pressure, and thereby keeps the pinion in proper position. To overcome this objection, I contemplate cntting the arbor A at a suitable point in its length in a curved manner, as shown at a', and after splitting the tube I press the same and then temper it, so that the split branches will sinkinto the cut portion and snugly embrace the same.

Having described my invention, what I claim isl, A means for fastening a gear pinion or wheel to a shaft or arbor, consisting in the combination of a pinion in one piece having a countersunk axial opening and a divided elastic friction-tube which is expanded in said axial opening and holds itsef in place on the arbor or shaft and the gear-pinion by tight frictional contact between the opposing faces, substantially as described.

2. A means for fastening a gear pinion 0r wheel to a shaft or arbor, consisting in the combination of a gear-pinion having its axial with opening provided with flared or beveled walls and an elastic divided friction-tube provided at one end with an undercut head which conforms to and is expanded in said axial opening ot' the gear-pinion by the arbor or shaft on which said friction-tube is fitted and which it tightly hugs solely by frictional Contact, substantially as described.

8. In a fastening for the cannon-pinions of watches and time keepers, the combination, with the arbor, of the pinion having an axial polygonal opening provided with the flared or beveled walls and a friction-tube which is divided or split from one end nearly its entire length and having a polygonal protubersuee or head at its split end, said protuberance or head being undercut or beveled and expanded in the axial opening of the pinion by the Shaft or arbor on which the tube is fitted and which it tightly hugs by frictional contact, substantially as described.

4. The arbor having the externally-cutout portion about midway of its length, in c0mbination with a cannonpinion having a split tube pressed and tempered so as to sink into the cut-out portion of the arbor, substantially as specified.

In testimony whereof I affix my signature in presence of two witnesses.

JOHN I3. JOBSON.`

Witnesses:

L. W. GRAY, J. S. BUDD.

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